<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        input:enabled{
            background-color: blanchedalmond;
        }
        input:disabled{
            background: blue;
        }
        input:focus{
            /* 聚焦 会匹配此选择器*/
            background: blueviolet;
        }
        input[type='checkbox']{
            /*去掉默认默认样式 */
            appearance: none; 
            width: 20px;
            height: 20px;
            border: 1px solid black;
        }
        input:checked{
            /* 在勾选框中，选中的情况进行匹配此选择器 */
            background: brown;
        }
        div::selection{
            /* 选中字体作用此标签 */
            background-color: blueviolet;
            color: cadetblue;
        }
    </style>
</head>
<body>
    <div>
        用户名：<input type="text">
    </div>
    <div>
        密码：<input type="text">
        <input  type="checkbox">
    </div>
    <input type="submit" value="提交" disabled>
    <div>
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    </div>
</body>
</html>